A multitude of wireless handsets, personal data assistants (PDAs), and pagers exist that feature microbrowsers for wireless access to the World Wide Web (Web). Wireless Web development standards are emerging from groups such as the Wireless Access Protocol (WAP) Forum™. However, these standards have yet to fully permeate the market. Therefore, handset and PDA manufacturers currently support several different protocols and markup languages. The plethora of protocols and languages create a problem for application developers trying to provide content that can be presented, with some consistency, across the widest range of devices. This is often referred to as the “Write Once, Render Anywhere” problem The WAP Forum is addressing this problem by standardizing on a markup language, Wireless Markup Language (WML), and providing a set of guidelines for developers. Although a tremendous help, WML does not cover the vast array of devices already on the market, not to mention those devices deployed with non-conformant software and services.
Most wireless Web enabled devices attach to a gateway or proxy system housed at a network carrier or Wireless Service Provider (WSP). FIG. 1 shows various methods of wireless Internet access. Most Web enabled phones 2 use the phone.com 3.x UP.Browser to request content from an origin Web server. Phone.com UP.Link gateways 3, housed at the carrier sites, process these requests, which are fulfilled over the Internet 4 via services 5. Newer phones and some pagers already support the WAP standards and they connect through a WAP gateway 6. Web-enabled Palm PDAs 7 pass through a proxy service 9, 10, which is supplied by Palm.net or OmniSky services, for example. All of these methods are similar, in that the wireless request passes through a gateway or proxy service, for example, UP.Link gateway 3, WAP gateway 6, and proxies 9, 10, to be translated into a wire-based HTTP/S request. Although the request model for the most common wireless Internet connections are similar, their underlying networks and device technologies differ. Wireless handset and PDA operating systems are usually delivered with a communication stack that abstracts the application developer from the underlying communication protocols and network technologies. Microbrowsers supplied on the wireless handsets and PDAs render hyperlinked markup content on the user interface display and enable user-directed navigation.
Currently, custom Web applications have to be developed for each specific device that uses different languages and protocols. Accordingly, there is a need for a uniform approach to content delivery to deliver an application to the broadest audience, across the widest possible set of devices.